


Guilty's too grand

by mrxsm



Category: Marvel Cinematic Universe, Thor (Movies)
Genre: Alternate Universe - College/University, Alternate Universe - Human, Blow Jobs, Clothed Sex, Drunk Sex, Dubious Consent, F/M, Frottage, Hand Jobs, Mutual Masturbation, Recreational Drug Use, Sibling Incest, Sloppy Makeouts, Trans Female Character, Underage Drinking
Language: English
Status: Completed
Published: 2018-09-26
Updated: 2018-09-30
Packaged: 2019-07-17 19:19:37
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,996
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16102118
Author URL: https://archiveofourown.org/users/mrxsm/pseuds/mrxsm
Summary: Thor's stomach lurched, head spinning from more than the gin now. He could smell it on Loki’s breath, taste it on her lips. He’d really just kissed his sister.Fuck.





	1. Chapter 1

**Author's Note:**

> chuck this on in the background if you want to take your immersion in this fic to the next level https://youtu.be/1ekZEVeXwek

Loki sighed, draping herself over the couch, her feet landing in her brother’s lap.

“I can’t believe I’m stuck here with you.”

Thor took another swig of the bottle in his hand, screwing up his face as he swallowed. “That makes two of us.”

It was some kind of gin he’d found in the liquor cabinet. Not his usual go to but it was three hours till midnight on New Years Eve and he was spending it alone with his sister. At their parent’s, of all places. The situation called for gin.

Loki clicked the power button on her phone on and off again, glancing at the quick flash of the screen. “He was supposed to be here over an hour ago. He hasn’t even seen my messages,” she complained. Her tone was contemptuous but Thor could see the hurt on her face.

“Asshole,” he remarked.

“Yeah.” She set her phone down and picked it up again, fingers ghosting over the buttons on the side.

“C’m here,” Thor said, reaching out and pulling Loki off the arm of the couch. She let herself be dragged down, ending up half on top of her brother. He wrapped his arm around her shoulders, squeezing tight. “Forget about him, he doesn’t know what he’s missing.”

He offered her the bottle in his other hand.

“Oh yeah? And what exactly is that?” She asked, turning to look at him and raising her eyebrow.

“Look, I'll be real with you, it doesn't taste great but it gets the job done,” he replied, trying to keep a straight face but unable to resist cracking a smile.

Loki smirked back at him, already reaching out to grab it.

“Uh uh,” he teased, jerking it out of her reach before letting her snatch it from him.

“Just don't tell mum,” Thor, joked, grinning. He knew full well underage drinking was probably the least stupid thing they'd gotten up to since moving out and he was certain their mum already knew about most of it.

Thor watched her take a smug sip, looking at him out of the corner of her eye. “Eugh.” Loki's lip curled up in disgust. “How are you drinking that straight?”

“I did warn you,” he chuckled.

Loki passed the bottle back like it had personally offended her, wiping the corner of her mouth with her fingers. Thor swallowed thickly as he watched her. He must already be feeling it. He was happy and warm and. . . content.

Loki had left her hair down tonight, messy curls hanging just past her shoulders and managing to look effortlessly good. He was the only other soul who knew just how much effort it had actually taken; how long she'd spent in the bathroom singing along to muffled ambient music. Thor still wasn't sure if it had been the same song on repeat, over and over again.

Her dark skirt was bunched up now, riding higher than it usually sat and Thor blushed at how much of her legs it revealed. They were propped up over him, her thighs resting on his, seperated only by her thin tights. He tore his eyes away, embarrassed, when Loki jumped up and grabbed the bottle off him, a dangerous glint in her eyes. 

“I'm making us cocktails,” she called back over her shoulder, already on her way to the kitchen.

Thor sighed, following her. He'd learned the hard way it was better to go along with her when she had that look on her face.

“It’s a shame they're coming back early now,” Loki remarked as she busied herself opening cupboard doors, looking for the necessary ingredients. “This place was made for parties. Remember my graduation?”

She'd pulled out a bag of oranges and was taking her time carefully cutting them into little slices.

Thor groaned. “You're evil.”

He didn't actually remember much of that night, but what he did made him wish he could remember less. Someone had to be the responsible one now, even if that meant cancelling what would have undoubtedly been a great New Year’s party at the last minute. And okay, maybe it was more out of fear of their Dad than a sense of responsibility, but it ended up in the same place.

“You’re welcome,” Loki retorted, proudly handing him a glass and leaning over the bench to watch his reaction. 

Thor felt her eyes on him as he took a sip. “Not bad,” he commented, nodding slowly and savouring the bitter taste. He opened his mouth to tease her again but decided to let her have this round. Loki was smiling softly now and that was rare enough already.

They stumbled back to the lounge room with their drinks, Loki dragging him along, spilling a bit of her’s on the way and Thor pretending not to notice. He was hyper aware of her hand on his thigh as they sat down again. He gulped down the rest of his drink, finishing it too quickly.

“So why are _you_ still here?” Loki asked, voice rising sharply.

“What do you mean?” 

“Well, what's everyone else doing now they're not coming here?” She snorted.

“Oh, right.” Thor's brow furrowed. “Nothing I was interested in,” he said simply.

Loki blinked but didn’t say anything to that. She got up and walked out of the room, leaving Thor to wonder what he'd done wrong.

It wasn’t long before she came back with another drink and a zip lock bag. Thor couldn't take his eyes off her as she sat down, tongue darting out to lick the paper in her hand. His gaze followed her fingers down as she wordlessly rolled the joint. 

It was still awkward, but they started to settle into a rhythm, passing it between them as they complained at length about the losers in their classes, their appalling housemates and everything else they’d missed from each other’s lives. The TV was on in the background and every time the conversation hit a wall they found themselves pretending to watch it intently until one of them could think of something else to say. 

The couch was more than big enough for two but they still found find themselves touching somehow, hands lingering just little too long as they exchanged the joint. At some point, Thor laid back, letting his head rest in his sister's lap. Loki giggled, shifting so she could run her fingers through Thor's hair.

She'd moved out for college two years after him and between their course loads, Thor's DnD sessions and Loki’s reading groups, they’d hardly had time to see each other during the week despite living only half an hour away.

Occasionally, they'd ended up at the same parties. Sometimes he'd see her dancing, eyes glassy as she ignored the guys who moved to grind up against her. Sometimes she'd be making out with people he didn't recognise, hands wandering over each other as much as they could get away with in the darkness of the crowded room.

She'd always kept her distance and Thor had let her. He'd assumed she wanted to build an identity separate from her older brother and he’d respected that, as much as he missed her company. 

More than once he'd found her clearly more fucked up than she was trying to let on. He’d insist on ordering her an Uber, and she'd let him, sitting silently through the ride home. Thor would stay for a while, making sure she had some water and got to bed okay before leaving for his own. Those times were always left unspoken between the two, both of them carrying on as though nothing had happened when they saw each other next.

This was the first time in he didn't know how long that Thor had had his sister's attention all to himself. He realised with a shock that he didn't want the night to end. 

“Oh shit, it's nearly midnight,” Loki's voice pulled him back, grounding him. She dived for the remote, turning the volume up.

Had they really been sitting here for hours already? How many of Loki’s delicious cocktails had he had? He’d lost track of that as well.

“I guess neither of us get a New Year’s kiss this year,” Thor sighed. “Just our luck.”

“You could kiss me,” Loki laughed, shrugging. She licked her lips.

“Five.”

“Four.”

Thor couldn’t help the warm laughter that bubbled up. 

“Three.”

He leaned in.

“Two.”

“One.”

They were still laughing when their lips met.

It only lasted a second and they were pulling apart before Thor even realised what had happened. They sat there for a moment, eyes wide, staring at one another. The fireworks on TV were lighting up the room now. Thor was vaguely aware some upbeat pop song was playing but he couldn't make it out over the sound of his heart pounding in his head.

They both moved at the same time, fumbling for each other. Loki’s tongue slipped into Thor's mouth and he met it with his own. Thor winced as their teeth clacked together, desperate to get as close as possible and too drunk to care about how it happened. Loki's tongue was sliding wet and insistent over his. It was sloppy and messy and all he could think of was that he wanted more. 

They broke away eventually, breathing hard.

Thor's stomach lurched, head spinning from more than the gin now. He could smell it on Loki’s breath, taste it on her lips. He’d really just kissed his sister. _Fuck_.

He wasn't sure when it had happened but all of a sudden Loki was holding his face, thumb brushing over his cheek. Thor's hands still sat awkwardly in his lap, not really knowing _where_ he should put them. He eventually settled for gently gripping Loki’s waist, as though there were an appropriate way to feel your sister up and this was it.

His other hand reached up to brush the hair out of her face before coming to rest at the back of her head, pulling her closer. She moaned into his mouth at that, her teeth playfully catching his bottom lip as she broke away to catch her breath.

He should say something. Put a stop to this before it went any further. They were drunk. And high. And there was no way she'd be trying to fuck her own brother if she - his thought was interrupted by Loki, who abruptly dragged his hand up to her breast, squeezing. Thor felt his cock twitch in his pants. _Fuck, fuck, fuck._

He allowed himself to spread his fingers, letting her nipple catch between them as he pushed upwards. Loki tensed, breath hitching. He did it again and was rewarded with a moan that went straight to his dick. Satisfied he'd gotten the message, she leaned forward, pressing their bodies together and kissing him deeply. He couldn't believe this was still happening, that they hadn't been struck down by lightning yet, somehow.

Loki was climbing into his lap properly now, tugging Thor's hand down and dragging his fingers along the inside of her thigh. He inhaled sharply when she finally reached her cock. She was just as hard as he was and Thor choked, nearly forgetting to breathe out again when she began to stroke herself with his hand. Okay, this was really happening. 

It felt less incriminating if he let her take the lead. And besides, he didn't want to stop now. If he stopped he'd actually have to _think_ about what they were doing and that's when words like 'incest’ and 'felony’ would probably be spoken instead of just ringing in the back of his mind.

It was all too easy for Thor to let Loki pull him down on top of her, her legs falling open to make way for him as she laid back on the couch. Her skirt was pulled right up around her waist now, her tights leaving nothing to the imagination.

Thor groaned at the sight of his sister spread out beneath him. He squeezed his eyes shut as he rolled his hips, grinding their erections together and holding onto Loki for dear life. 

Tentatively, he reached up under her shirt to feel her chest again. Her skin was warm to the touch, her small tits fitting perfectly in his hand as he massaged her. Loki gasped, twitching, when he rolled her nipple between his fingers.

“Yes,” she breathed. 

Thor reached across to play with the other one, mouth trailing wet kisses over her neck, lapping at the sweat clinging to her collarbone. He grazed his teeth across the soft skin there, nipping gently and sucking as Loki cried out before reality hit him again. He froze with the realisation he shouldn't leave anything too obvious.

“Should I. . .” Loki trailed off, reaching to pull her shirt off.

Thor buried his face in her neck, shaking slightly. “This is fine,” he choked out.

He wanted nothing more than to see Loki laid out before him completely, to memorise her every detail in case he never got to touch her like this again. But the moment they started taking off their clothes there could be no denying what they were doing. Somehow, that felt like crossing a line.

Loki didn't seem to mind. She continued to move her hips so their cocks rubbed together, trapped between their clothes and their stomachs. Every desperate little sound she let slip was bringing Thor closer to the edge. Loki whined when Thor’s mouth found her neck again, grabbing his ass. Her fingers were digging into him painfully now as she rocked, pulling him into her.

“Thor,” she sobbed, and Thor gasped, mouth open, gaping as he came, come pulsing through his jeans. 

“I’m -”

“I’m -”

Loki turned to bury her face in the pillow, her nails raking along his back as her hips bucked up once, twice, her entire body arching up into him. Thor slipped his arms under her back, holding her tight against him as she came. He could feel the wetness spreading, soaking through her tights and onto his shirt, joining his own mess - the awful evidence of what they'd done. 

Thor collapsed with her, head falling to rest on her chest. Loki was trembling, little aftershocks running up her body. Thor was still panting and every slight movement of his caused Loki to groan and twitch again, totally overwhelmed.

When Thor came to again, he carefully pried himself up so he was lying more alongside Loki than on her. He wasn’t sure how long he’d been lying there for, only that he’d meant to move a long time ago.

It wasn’t quite morning yet but their clothes were stiff now, the crusty patches on Thor's shirt grating uncomfortably against his skin. He tried not to think about it, willing himself back to sleep. Loki mumbled something incoherent as he shuffled, trying to get comfortable. She turned, wrapping her arm around him and tucking her face into his neck.

Thor drifted off again like that, to the feeling of Loki's hot breath on him and the sound of dogs barking in the distance.


	2. Chapter 2

Loki woke slowly. She swallowed, mouth dry, her chest rising and falling in time with her brother’s. Her brother who she had just slept with.

Maybe if she didn't move, the situation would be less terrifying. If she never got up she'd never have to confront the reality of what had happened last night. As far as she could tell, Thor was still asleep, but she couldn't bring herself to open her eyes to check. Actually seeing her brother next to her would make it all too real.

Loki wanted to be able to savour the intimacy of this moment but her mind was still reeling. Thor had gone along with her willingly enough at the time, but she couldn't imagine him ever wanting to be in the same room as her again - let alone touch her - once the weight of what they'd done had sunk in. And she only had herself to blame. She was still lying there when her eyes flew open at the click of the key in the front door. No way could their parents find them like this. 

She moved too quickly, head pounding as she disentangled herself from Thor, leaping up and pulling her skirt down. Eugh. She needed water. Immediately.

She staggered to bathroom, grabbing the glass that had doubled as their makeshift ashtray on her way out. Definitely less compromising in the grand scheme of things, but nothing she wanted to shove in their parents’ faces. She’d have to get rid of it properly later.

Tripping over her feet as she shook off her clothes, she steadied herself, turning on the taps. Everything was still spinning slightly. She cupped her hands, gulping down a couple mouthfuls of lukewarm water before sinking to the shower floor and letting it run over her. It did nothing to clear her head. 

Loki had tried to have fun since moving out. And she had, sometimes. The problem was that none of them were _Thor_. So she’d done the only logical thing and looked for excuses to avoid him. Better that than confront him with the depth of what she felt and lose him forever.

But she’d forgotten just how easy it was to let her guard down around him. And if Loki pushed the boundaries a little when they were drunk, with her hand on his thigh, she could always laugh it off. Plausible deniability and all. At some point, that had to run out though. Probably somewhere around the time she stuck her tongue in his mouth. She screwed up her eyes, fingers running up and down her face as more details came back to her. 

In a way, she'd gotten what she'd wanted. But it had always seemed better in theory. In practice it was so much messier. Could you even _have_ informed consent for something like this?

She banged her head against the shower wall, letting it rest there. Fucking her brother, what a way to start the new year. But it wasn’t as though they’d actually fucked, not really. And so not _technically_ illegal in the eyes of the law. She wished that was comforting instead of something that left a bitter taste in her mouth. 

Thor was gone when she got out. They spent the rest of the morning sneaking around the house, guiltily avoiding their parents and one another.

It was nearly midday before they eventually ran into each other in the kitchen. Her brother was cooking bacon and eggs, the smell simultaneously making Loki hungry and nauseous. She ignored him, walking carefully around the room to put the kettle on. The ease at which they moved together last night was gone, replaced instead with a nervous uncertainty. Loki fidgeted with the sleeves of her shirt, unsure how to exist around Thor again. This was far worse than never having kissed him at all. 

She tensed when Thor finally broke the silence. “Loki,” he said softly. “We should talk.”

“Really?” She sneered, avoiding his eyes and trying to look busy. If she looked busy it wouldn't be so obvious she would rather die than be here, having this conversation. “What's there to talk about?” 

Thor gaped at her, looking around before he leaned in conspiratorially. “We had sex,” he whispered furiously.

“Is that what it was?” Loki replied, low and quiet. Her mouth was still dry.

“Fuck, shit, I don't know. I’m sorry.” Thor was looking around the room desperately, as if he'd find the the right thing to say there somewhere. “I just don't want to. . . I don't know. Take advantage of you, or something,” he mumbled, voice wavering. “You're my little sister.”

“We're adults, Thor,” Loki snapped. “We made a drunken mistake, it happens all the time.” Usually not with your brother, granted, but it wouldn't be the first time she'd left someone's house in the early hours of the morning to hurried _I'm sorry’s_ and fleeting eye contact. It managed to hurt so much more when it was Thor.

Thor looked almost disappointed, as though he'd been expecting her to say something different. “What do we do now?” He asked after a while.

It would have been impossible for her to suggest they try and forget it. She knew she'd never be able to and it would be unfair to ask the same of him. But what else could they do now except go back to keeping their distance and do their best to move on?

“Just tell me we're okay,” Thor begged.

Loki wasn't sure she'd ever be okay again but Thor looked like he was about to cry and she absolutely wasn't going to deal with that. She jerked her head, nodding slightly and Thor visibly relaxed, shoulders slumping.

“I’m sorry,” he whispered again, reaching for her hand. “It was so selfish of me.”

Loki almost tore it away, but she let him cover her fingers with his, squeezing slightly. _Selfish_. She found herself speaking before she could stop herself. “What do you mean? You’re not actually saying you enjoyed it, right?” She laughed bitterly.

Thor shuffled now, his voice barely audible. “Loki. . . of course. Of course I did, that’s the problem.”

Now the room was spinning for real. Loki thought she was going to throw up for the first time since last night. There was no way this was happening, no way her perfect brother could be as fucked up as her. She breathed in, blinking back the tears that sprang to her eyes. She couldn’t find the words she wanted to express how she felt. She wasn’t sure they even existed. 

“You fucking idiot,” is what came out.

“Wh -”

Loki replied by closing the distance between them, lips smashing together awkwardly, noses bumping. Thor folded into her instinctively, hands coming to rest on her shoulders before breaking the kiss.

“Did you? Want it?” He breathed into Loki's mouth, eyes locked with her’s now, searching.

God. He was going to make her say it. “Thor,” Loki sighed, in a rare moment of honesty. “I’ve never wanted anything more in my life.”

Without warning, Thor pulled her up by the waist so she was sitting on edge of the bench, leaning in between her legs to kiss her again. Loki yelped, pushing him away. “Not here! What are you thinking?”

Thor was smiling fondly, Loki’s hair falling over his face. He pulled it aside to kiss her once more, tongue licking her lips open and Loki letting him, heart beating wildly. This was probably the second most stupid thing she’d ever done and both were happening within the same 24 hours. 

Thor froze suddenly. “Oh shit. The eggs!”

Loki managed a laugh now, as he tried to salvage what he could of his breakfast, sadly scraping off the bits that weren’t fit for human consumption. He scowled at her. “I was going to do some for you too, you know.”

“If they were going to turn out anything like that, don’t bother.” She shot back, the corner of her mouth still turned up in a smile. They couldn’t go back to what they had before, but it wasn’t as though either of them wanted to. Maybe, just maybe, they could make this work. 

They ordered pizza in the end, eating it on Thor’s bed because Loki refused on principle to let Thor anywhere near her’s with food. She was feeling more human now, headache receding as Thor lazily pressed kisses to her face, neck, hands, everywhere he could reach. Their fingers danced over each other’s bodies, still getting used to the fact that they were allowed to have this. Both of them paused when Loki’s found the bare skin between Thor’s shirt and pants.

“Is this okay?”

“Yes,” came Thor’s soft reply. 

Loki ran her hand along the soft hairs that covered Thor’s stomach. She bent down, kissing a trail upwards and Thor reached up to pull his shirt the rest of the way off before she found his mouth again. It was slower than last night, both of them taking their time trying to fit together and find an easy rhythm. Thor shifted his leg, allowing Loki to slide her’s in between. She could already feel his cock beginning to harden. Thor bit his lip, letting her rock into him, appreciating the look of awe on her face. 

“Alright?” 

Thor moaned out a yes, lifting his hips up to allow her to slide his pants off. He was a little bigger than Loki, but a good deal thicker. She reached out, still hesitant, feeling the weight of him in her hand.

“Can I touch you too?” Thor breathed.

Loki nodded, face flushed, as she pulled her top off and reached down to unzip her jeans.

Thor drank in the sight of his sister in front of him. “I’ve got an idea,” he said. “Come here.” He motioned for her to lay back in his arms as he propped himself up on the pillows. 

Her warm body was flush against Thor’s now and she hooked one of her legs over his thigh, leaning into his embrace. He reached out, running his hand down over her chest until he reached her length, wrapping his fingers around her and stroking experimentally. Loki gasped softly.

“You’re clean, yeah?”

Thor nodded.

“Me too, by the way,” Loki offered.

She reached out for Thor, brushing her thumb over the head of his cock to catch the precome already leaking out. Raising her fingers to her mouth, her tongue darted out and lapped it up, slipping her fingers further in. She could feel Thor’s breath catch as she hollowed her cheeks, dragging her fingers slowly in and out. Thor groaned at the sight, hand snaking up to the back of her head and pulling her in for a kiss. Loki opened her mouth, letting her brother taste himself on her.

“The things you do to me,” Thor complained, not annoyed in the slightest. 

Loki grinned at him. Emboldened, she wrapped her slick fingers around Thor’s cock again, pumping him slowly.

“Yeah, just like that.”

Loki swelled with pride as she watched Thor come undone by her hand. She realised now that her guilty fantasies had never really done it justice. 

“You look so good like this, brother,” Loki breathed. She hesitated, catching herself too late, the words already out of her mouth. Probably best not remind him they were related right now. But Thor, to his credit, didn’t falter. If anything, he seemed to grow even harder in her hand. Interesting. 

Loki’s own response must have been similarly encouraging. Thor was stroking her with increasing confidence now, matching her speed and watching her carefully to try and find out exactly how she liked to be touched.

Thor closed his eyes briefly, lips tight, willing himself to last longer. Despite his best efforts, his grip faltered as he came, spilling over Loki's hand with a cry. After a moment, he reached over for the tissues beside her bed, but Loki had already pulled her fingers back into her mouth, swirling her tongue around and sucking them clean.

“May I?” She asked, leaning down, breath hot on Thor’s stomach.

Thor simply nodded, shocked, as his sister begun to lap at the come spattered across his middle before moving down to take his softening cock into her mouth. He jerked, still sensitive as she gently sucked him.

“Loki,” he gasped out. “I think I need a moment.”

She gave a final lick before rising again, satisfied. Loki was still hard herself, cock jutting out and dripping now. Thor took a hold of it again, leaning into her and mouthing at her neck. He moved down and found her nipple, flicking it with his tongue before latching on and _sucking_ and Loki moaned. She reached up to tangle her fingers in his hair, pulling and holding him there as she thrust up into his hand.

Loki was letting out a series of _Thor’s_ and _yes’s_ now, hips moving erratically. Thor stopped all of a sudden, kneeling to move down her body and she let out a low whine before realising what he had in mind.

“Yes, please,” she said, fingers running through his hair again as he kissed up her thighs.

Thor looked up at her as reached her cock, licking a long stripe along her length. Loki’s grip on his hair tightened in anticipation. She couldn’t help herself when he finally wrapped his lips around her, thrusting up into the warm heat of Thor’s mouth. He moaned around her, tongue swiping over the head as he pulled back to admire his work.

Thor must have been pleased with what he saw because he grinned as he bent back over, lips sliding up and down again, and it wasn't long before Loki was coming in his mouth. He choked a little as her hips pushed her cock in even further, hitting the back of his throat, but he was still grinning as he swallowed. They were both breathing hard as Thor wiped his mouth and pulled Loki into his arms again. They stayed there like that, watching the light from the window above gradually disappear until they were left in darkness.

“Shower?” Thor asked, after what could have been minutes or hours.

Loki groaned, showing no sign of moving. She really should - they were sweaty and gross and she really didn’t want to fall asleep like that again, no matter how tempting it was. Besides, it seemed like she'd have plenty more opportunities to fall asleep in her brother's arms in the future. Their future. She still panicked if she thought about it too much, but it was easy not to when Thor was holding her like this, as though it was the most natural thing in the world.

“Shower,” she agreed, giving him a peck on the cheek.


End file.
